1. Field of the Invention
The present invention relates to a position detecting apparatus that detects a position of a driving member which linearly moves or rotates, and particularly to a magnetic position detecting apparatus using magnetism.
2. Description of the Related Art
As a position detecting apparatus of this kind, Examined Japanese Patent Publication No. 54-41335 (patent document 1) discloses a structure in which first and second magnetic resistance circuits, each having multiple magnetic resistance elements connected in series, are formed in a comblike shape and the first and the second magnetic resistance circuits are horizontally arranged along a magnetic pole array direction.
Unexamined Japanese Patent Publication No. 7-4987 (patent document 2) discloses a technique in which a groove is formed on a magnetized surface to shape an output waveform from a magnetic resistance circuit at a reference position.
However, in the technique of patent document 1, since the multiple magnetic resistance circuits in the magnetic position detecting apparatus are arranged along the magnetic pole array direction, when one magnetic resistance circuit has numerous magnetic resistance elements or numerous magnetic resistance circuits are provided, there is a problem in which the length in the circuit in the magnetic pole array direction is increased to cause enlargement in size of the position detecting apparatus and a decrease in resolution of the output waveform.
Moreover, in patent document 2, when the multiple magnetic resistance circuits are provided, there occurs a problem of enlargement in size of the position detecting apparatus, similar to patent document 1. Moreover, in the position detecting apparatus of the driving member that rotates, there is a problem in which when a length of a position detecting apparatus in a width direction is increased, electric field strength received at both ends of the width direction of the position detecting apparatus is reduced by its positional shift, so that resolution of the output waveform is decreased.